3 or 4 on a 92 Force 90Hp

[bkhealey]

Hi everyone, I have a 3 blade 13 1/2 prop on my 1992 bayliner with a 90 HP force. with just me I can get up to 38 WOT. With a 3 people and a skier it's a little hard getting them out and going. I also like to cruise with 6 friends every now and then and want to smooth it out. Would like to get up on plane faster. Don't care if I lose a few MPH on the top end. Looking at a 4 Blade 15 pitch prop. From what I have been reading this should be just about right. I was told I would want to drop to a 15 when going to 4 blades. That I should lose maybe 2-3 MPH. Does that sound about right?

Thanks!

Brian

 

[steelespike]

13 1/2 sounds like a diameter? can you give us your diameter and pitch.
We need to know the prop size,rpm and gps speed.Your present rpm and speed would help determine
Your prop selection.

 

[batman99]

My previous Bayliner 1700 with Force 120 I4 motor had a 3-blade 21 pitch. Way too sluggish on the bottom end. I replaced with 3-blade 19 pitch and it was still too sluggish on bottom end for water sports. I then replaced with 4-blade 17 pitch and was pleased with it. Exact same boat with replacement Johnson 115 V4 motor came with 3-blade 19 pitch and I found it a little sluggish on bottom end. Me thinks a 3-blade 17 pitch would be perfect for average person "medium weight load / long distance cruising" usage. For our Johnson V4 motor (which likes higher RPMs), I'm now currently replacing with 4 blade 15 pitch - since we do more water sports than long distance cursing. 4-Blade is most often better for water sports / heavy weight loading usage.

Long mumblings short.... Do focus on 4-blade that is 2 pitches lower than your long distance cruising 3 blade. Depending on your daily usage, install the 3-blade or the 4-blade. Only takes a few minutes to swap out props. Yes. A smaller size pitch 4 blade is a littler higher on RPMs a little harder on fuel but bottom end increase (for water sports or heavy loading) is worth it... This approach works for my Bayliner... Hope this helps...

 

[Sea Rider]

If like skiing should do it with just driver, a spotter if needed and skier and go for a prop that achieves full wot rpm range for that engine on flat calm no wind water cond. Get another prop to boat with 6 to achieve at least medium to max wot rpm. Can't do sports + boating heavily loaded with just one prop, unless it's a adjustable pitch prop for different boating scenarios.

Happy Boating

 

[SkiDad]

my boat will hit 40 with a 19" pitch - fine pull for combo skis but not good for slaloming - 17 is fine for slalom as long as I only have 4 on board. i have a a few 15 pitch 3 blades and they pop multiples skier up with a full boat. The penalty is that I only hit around 36 mph with a full boat but we are into skiing. I leave the 15 pitch on all the time b/c the boat doesn't ever struggle to tow.

i believe the 90 is rated for 5250 rpm - so you want to prop it as close to that as you can - maybe 100 over is OK too. Michigan makes good props for the force some props require the anode to be taken off depending on what lower unit you have.